1. Field
The present disclosure relates to a washing machine and, more particularly, to a washing machine which is capable of effectively attenuating vibrations.
2. Description of the Related Art
Generally, a washing machine is an apparatus that washes laundry using, for example, emulsified detergent, water streams generated by the rotation of a wash tub or a pulsator, and shocks applied by the pulsator. The washing machine implements washing, rinsing, and/or dehydration to remove contaminants attached to the laundry (hereinafter referred to as “clothing”) using the action of detergent and water.
A conventional washing machine includes a casing defining the external appearance of the washing machine, an outer tub disposed inside the casing in a suspended form, and an inner tub rotatably provided inside the outer tub. Additionally, the washing machine further includes a suspension to prevent the outer tub from vibrating due to the rotation of the inner tub and/or the pulsator.
The suspension is typically configured to attenuate vibrations generated from the outer tub using, for example, the elasticity/restoration of springs or the viscosity of fluid. However, although this suspension may effectively attenuate vibrations in the normal vibration state, in which the outer tub vibrates within a given amplitude range, it is limited in the attenuation of vibrations in the excessive vibration state, in which the outer tub vibrates at a greater amplitude than that of the normal vibration state.
That is, in the case where the typical suspension is designed to be optimized for the excessive vibration state exhibiting a greater amplitude, the ability to attenuate normal vibrations, having a relatively small amplitude, is deteriorated. In contrast, in the case where the typical suspension is designed to be optimized for the normal vibration state, vibration attenuation sufficient to attenuate excessive vibrations cannot be expected. Therefore, there is a need to find a method for effectively attenuating vibrations both in the normal vibration state and the excessive vibration state.
In addition, although the typical suspension functions to attenuate vibrations by converting vibration into heat via friction between a support rod and a friction member moving along the support rod, this may problematically cause thermal degeneration of the friction member due to frictional heat or also cause deterioration of friction as the friction member sticks to the support rod. In particular, lubricant is applied to the support rod, in order to maintain a constant viscosity between the support rod and the friction member and to prevent overheating caused by friction. In the conventional washing machine, it is difficult to supplement the lubricant during the process of maintenance and repair.
In addition, although most constituent components of the suspension are formed by injection molding a synthetic resin, such molding becomes difficult as the structure in which the friction member is to be received becomes complicated. The constituent components of the suspension must have sufficient durability because they are operated in connection with elastic members such as springs during the vibration of the outer tub, and some portions, which need a great material thickness for durability, may be constricted during injection molding.